RF cavities are known which can be excited into RF resonance by coupling RF power into the RF cavity. The RF power itself, however, is generated at a distance from the RF cavity, for example with the aid of a klystron, and transported to the RF cavity with the aid of a waveguide. As an alternative, it is possible to couple the RF power into the cavity with the aid of an antenna or an inductive coupler.
U.S. Pat. No. 5,497,050 discloses a different structure for coupling RF power into an RF cavity. This is done using a multiplicity of solid-state power transistors, which are integrated in a conductive wall of the RF cavity.